Drafting instrument

ABSTRACT

This invention provides a mobile integral drafting instrument comprising a straight edge having a first clutch mechanism to provide vertical movement thereof on a drawing media and a second clutch mechanism to provide a circular movement thereof for drawing free and predetermined angles, straight lines and curved lines without the aid of additional instruments.

United States Patent 11 1 1111 3,835,542

DeMathe Sept. 17, 1974 DRAFTING INSTRUMENT 3,462,846 8/1969 Goerz 33/109[76] Invento Lesl e L. DeMathe, 2020 W 3,726,017 4/1973 DeMathe 33/10992801 668,266 9/1964 Italy 33/109 [22] Flled: 1972 Primary ExaminerLouisR. Prince [21] Appl. No.: 281,315 Assistant E.\'aminerChar1es E.Phillips Attorney, Agent, or Firm-Roman A. DiMeo [52] U.S. Cl 33/109,33/DIG. 1, 33/27 C i 51 1111. c1 B431 13/02 7 ABSTRAC T 5 Field f S h33/D]G l 27 E, 109 27 R T1118 1nvent1on Pi'QVldES a moblle 1ntegraldraftmg 1nstrument compnsm a stra1ght edge havm a first 33/27 B, 27 C,DIG. 12 g g clutch mechanism to provide vertical movement [56]References Cited thereof on a drawing media and a second clutch UNITEDSTATES PATENTS mechanism to pr0v1de a c1rcular movement thereof I fordrawing free and predetermined angles, straight Carmen] 33/109 lines andcurved lines without the aid of additional in- 1,051:712 1/1913 strumems1,111,174 9/1914 Ostringer 33/109 25 Claims, 13 Drawing Figures DRAFTINGINSTRUMENT This invention relates to instruments in the mechanical andtechnical drafting field and more particularly to instruments fordrawing angles, straight lines, and

curves.

Heretofore in the field of mechanical or technical drafting, straightedges, protractors, rulers and other measuring devices, compasses,T-squares and triangles, either as separate elements or in conjunctionwith each other, were required in order to measure and/or draw straightlines, angles and curved lines. Of necessity, this required a number ofseparate drawing instruments to obtain a desired result.

The instant invention eliminates the necessity of protractors,compasses, T-squares, straight edges, triangles and rulers by providingan integral mechanical drafting instrument having a unique clutchmechanism which permits the performance of all of the foregoingfunctions.

The drawing instrument of the instant invention is comprised of a Hatstraight edge having predetermined measuring indicia thereon and acircular or semicircular portion also provided with predeterminedmeasuring indicia. Associated with the flat edge portion of theinstrument and the circular portion thereof are independent clutchmechanisms which, when selectively applied, will result in solely avertical movement on a drawing media or a circular movement of theinstrument upon the drawing media, as will hereinafter be more fullydescribed. In addition, by concurrently activating both clutchmechanisms, a unique braking action is achieved which prohibits eithervertical, horizontal or circular motion of the instrument.

This invention further provides a means to absorb and eliminateundesirable lateral or horizontal motion of the instrument. I

It is therefore the object of this invention to provide a simple,mobile, integral mechanical drafting instrument for drawing straightlines, angles and curved lines without the use of extraneous instrument.

A further object is to provide a simple, mobile, integral mechanicaldrafting instrument which can be activated in a preselected vertical orcircular track without the use of extraneous instruments.

Another object is to provide a simple, mobile, integral mechanicaldrafting instrument which is provided with a simple clutch means forselective movement of the instrument in a vertical or circular directionwithout the use of extraneous instruments.

Yet another object is to provide a simple, mobile, integral mechanicaldrafting instrument which has a simple unique braking mechanism toprohibit movement of the instrument in any direction without the use ofextraneous instruments.

Yet a further object is to provide a simple, mobile, integral mechanicaldrafting instrument which is capable of drawing a plurality ofpredetermined parallel lines and a plurality of concentric circularlines without the use of extraneous instruments.

Other objects and advantages will be readily apparent from the followingdescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a top plan view of the instrument of the instant invention;

FIG. 2 is an elevational view of the right side of the instrument ofFIG. 1 showing the actuating wheels in their inoperative positions;

FIG. 2A is an elevational view similar to FIG. 2 except that theactuating wheels are shown in their operative braking positions;

FIG. 3 is a front elevational view of the instrument of FIG. 1illustrating the actuating wheels for providing vertical movement intheir inoperative position;

FIG. 3A is an elevational view similar to FIG. 3 except that theactuating wheels and axle are illustrated in their operative position;

FIG. 4 is a cross-sectional view of the magnetic holder and retractorfor the axle of the vertical movement actuating wheels taken on the line4-4 of FIG.

FIG. 4A is a view similar to FIG. 4 except taken on the line 4A4A ofFIG. 3A;

FIG. 5 is a front elevational view, partly sectioned of the instrumenttaken on the line 5-5 of FIG. 1 showing the actuating wheel forproviding circular movement in its inoperative position;

FIG. 5A is a front elevational view, partly sectioned similar to FIG. 5except that the actuating wheel and axle for circular movement are intheir operative positions;

FIG. 6 is a cross-sectional view of the magnetic holder and retractorfor the axle of the circular movement actuating wheel taken on the line66 of FIG. 5;

FIG. 6A is a view similar to FIG. 6 except taken on the line 6A-6A ofFIG. 5A;

FIG. 7 is a side elevational view of the vertical movement actuatingwheels and axle; and

FIG. 8 is a side elevational view of the circular movement actuatingwheel and axle;

Referring more particularly to FIG. 1, reference numeral 10 designatesgenerally the integral drafting instrument of the instant inventionhaving a flat, elongated, straight edge portion 10a provided withpredetermined measuring indicia 11 along the edges thereof and a flatcircular or simicircular portion 10b provided with predeterminedmeasuring indicia 12 in a circular pattern thereon. Straight edgeportion is also provided with openings 13 passing through the facethereof (as best seen in FIGS. 3 and 5).

A first clutch means positioned on straight edge portion 10a, said firstclutch means comprised of actuating wheels 14 for providing verticalmovement interconnected by elongated shaft or axle 15 which continuesthrough said wheels 14 and are secured at each end by a housing guide16. (See FIGS. 1, 3, 3A and 7). Axle 15 may be of any material which issusceptible to magnetic flux.

Housing guides 16 are provided with recesses for accommodating the endsof axle 15 so as to prohibit forward movement of the axle relative tothe straight edge portion 10a yet allow limited axial and verticalmovement thereof relative to housing guide 16.

Axle 15 passes through retraction and maintenance means 17 each of whichincludes a magnet 17a spatially positioned from the face of straightedge portion 100. (As best seen in FIGS. 4 and 4A). By virtue of magnet17a, retraction and maintenance means 17 serve to hold axle 15 elevatedrelative to the face of straight edge portion 10a, and concomitantlymaintaining wheels 14, in disengaged relationship to the drawing media.When a sufficient downward normal force is applied to axle 15 so as toovercome the magnetic force of magnet 17a on said axle, the axle isdisengaged and normally downwardly displaced toward the straight edgeportion a, and concomitantly the drawing media, so that wheels 14 passthrough openings 13 and engage said drawing media.

It should be noted that although a pair of retraction and maintenancemeans 17 are herein disclosed, any number consistent with desired designmay be utilized without departing from the scope of the inventionherein. It should be further noted that although the retraction andmaintenance means 17 herein disclosed utilize a magnet 17a inconjunction with an axle composed of material susceptible to magneticflux, spring means and the like may be utilized in said retraction andmaintenance means without departing from the scope of the inventionherein. However, it should be noted that the use of magnetic retractionand maintenance means is preferable since an application of forceagainst a resistant spring means may transmit said force to the straightedge portion 10a of the instrument and concomitantly to the drawingmedia, thereby creating a friction between said drawing media and thesaid straight edge portion.

A contact bar 18 engages axle 15 and is carried thereby so as to be freefrom contact with the face of straight edge portion 10a. Although anumber of conventional means may be utilized to attach said contact bar18 to the axle 15, as disclosed herein said contact bar is tubular andis provided with an axial split separating the wall member thereof sothat the same may be snapped onto axle 15. Thus contact bar 18 isengaged about axle 15, yet suspended away from surface of straight edgeportion 10a.

Upon the application of a normal force to contact bar 18 said normalforce is transmitted to axle 15 causing said axle to flex downwardly andsubsequently disengage from magnet 17a of retraction and maintenancemeans 17. Thus wheels 14 are caused to engage the drawing media so thatupon the application of an additional vertical force along the plane ofthe drawing media (as designated by arrow A in FIG. 1) the instrument ofthe instant invention will travel in that predetermined direction. Itshould be noted that at no time, whether or not an actual force isapplied to contact bar 18, said contact bar does not contact the surfaceof straight edge portion 10a. Thus, none of the normal force istransmitted to the face of straight edge portion 10a and press saidstraight edge portion against the drawing media to cause detrimentalfrictional resistance during the vertical travel of the instrument.

Upon the release of the aforementioned axial force to contact bar 18,the magnetic force of magnets 17a retract axle 15 in the reverse normaldirection thereby lifting wheels 14 from engagement with the drawingmedia.

ter-productive to the first mentioned spring means and equalize oreliminate the effectiveness of the first mentioned spring means.

Associated with the circular or semi-circular portion 10b of thedrafting instrument herein is a second separate clutch means consistingof an actuating wheel 20 for providing circular movement of the draftinginstrument in the direction indicated by arrow B in FIG. 1 (See FIGS. 1,5 and 5A). Said second clutch means is further comprised of a spindle oraxle 21 passing through said actuating wheel 20 said actuating wheelbeing rotatable about axle 21. Axle 21 has one end thereof 21a formed ata substantially right angle to the axis of said axle. (As best shown inFIG. 8). The opposite end of axle 21 is accommodated in a housing guide22 which is provided with a guide slot (not shown) for accommodatingsaid opposite end of axle 21. It should be noted that the guide slotallows the end of axle 21 to move in a plane normal to the face ofsemicircular portion 10b but prohibits movement of axle 21 in a planeparallel to the face of said semicircular portion. The formed end 21a ofaxle 21 is in slideable engagement with aperture 23 which is situated atthe center of the diameter of said semicircular portion 10b.

The second clutch means further includes a retraction and maintenancemeans 24 provided with a mag net 24a which performs the same function asdid magnet 17a of retraction and maintenance means 17 included in thefirst mentioned clutch means. Also, as was the case in the first clutchmeans, a contact bar 25 is carried by axle 21 which is similar instructure and function as contact bar 18 associated with axle 2!. Thus,upon the application of a normal force to contact bar 25, axle 21 isdisengaged from the magnetic force of magnet 24a and axle 21 is therebydisplaced normally from the face of semicircular portion 10b therebycausing the formed end 21a of axle 21 to pass through aperture 23 andengage drawing media, while actuating wheel 20 concurrently passesthrough opening 26 in straight edge portion 10a and likewise engages thedrawing media.

Thus the application of an additional force parallel to the plane of thedrawing media while maintaining a normal force on contact bar 25, willcause the instrument to rotate in a circular path as indicated by ArrowB in H0. 1. Upon the release of said normal force upon contact bar 25,magnet 24 will retract axle 21, thereby disengaging the formed end 21athereof and actuating wheel 20 from the drawing media. To insure apositive engagement of formed end portion 210 of axle 21 with thedrawing media, a sharp point 21b may be located at the extreme end ofsaid formed end so that said end is lightly embedded in the drawingmedia.

Although a disengagement of actuating wheels 14 and 20 from the drawingmedia would allow the instrument of the instant invention to lay flat onsaid drawing media without movement in any direction, in order topositively prohibit movement of the drawing instrument in any directiona braking effect is realized by simultaneously applying a normal forceto contact bar 18 and to contact bar 25 so that actuating wheels 14 and20 simultaneously engage the drawing media. This is due to the fact thatthe axis of axle 21 is not parallel to the axis of axle 15 so thatrotation of the wheels about their respective axis is prohibited.

It should be noted that the upper right-hand quadrant of semicircuiarposition 10b is omitted. Further, the adjacent upper left-hand quadrantof said semicircular portion 101; has a cut-out portion so that thecircumference of the modified quadrant is concentric withthe outercircumference of semicircular portion b. Of course, the measuringindicia 12 is consistent not only through the original quadrant and themodified quadrant, but continues across the face of the straight edgeportion 10a so that in effect, three quadrants of the circle arerepresented.

The measuring indicia 12 of semicircular portion of 10b, as is the caseat measuring indicia 11 of straight edge portion 10a, are predeterminedto read measured distances, angles and the like, or may be utilizedprimarily for reference points.

The off-set circumferential edge of the upper lefthand quadrant andlower left-hand quadrant of semicircular portion 10b both intersect atshoulder 27. (As best seen in FIG. 1). Diametrically across fromshoulder 27, by omission of the right-hand quadrant of the semicircularportion 10b, a second shoulder 28 is formed which is situated in thesame plane as shoulder 27.

Shoulders 27 and 28, and leading edge 29 of straight edge portion 10aall lay in the same plane which passes slightly below, and parallel tothe true diameter passing through the center of semicircular position10b so that shoulder 27 and 28 and the forward edge 29 of straight edgeposition 10a are slightly off-set below a said true diameter.

The off-set shoulders 27, 28 of semicircular position 10b and forwardedge 29 of straight edge portion 10a provides an automatic alignment ofthe marking instrument along the forward edge 29 of straight edgeportion 10aand shoulders 27 and 28 with the true diameter of thesemicircular portion 10b. Thus a true reference line may be easilyestablished to assist the draftsman in the preparation of his drawingsand the like.

While one embodiment of the invention has been described, it isunderstood that the particular embodiment of the invention hereindisclosed is for illustrative purposes only and the various changes maybe made therein without departure from the principles of the invention.

I claim:

1. An integral, mobile drafting instrument, comprismg:

a body, said body having a straight edge portion and a circular portion,said body having a plurality of openings passing therethrough,

a first clutch means carried by said body for providing forward motionto said body relative to a drawing media or the like upon theapplication of an extraneous force thereto, said first clutch meansbeing comprised of first rotatable contact means having spindle meanssecured thereto, means for accepting an extraneous force carried by saidspindle means for lowering said rotatable contact means through saidopenings into an operative position, means for retracting said firstrotatable contact means from an operative to an inoperative position bywithdrawing from said openings, means for preventing lateral movement ofsaid first rotatable contact means due to transient forces, and

a second clutch means carried by said body for providing rotationalmotion to said body relative to a drawing media or the like upon theapplication of an extraneous force thereto, said second clutch meansbeing comprised of a second rotatable contact means having spindle meansrotatably secured thereto, said second rotatable means situated in thesame plane as said first rotatable contact means, the axis of rotationof said second rotatable contact means being angled with respect to theaxis of rotation of said first rotatable contact means, said spindlemeans having one end thereof formed normally to the axis of said spindlemeans so as to be slideably accommodated in an opening passing throughthe body, said opening being located at the radial center of thecircular portion of the body, means for accepting an extraneous forcecarried by said spindle means for lowering said second rotatable contactmeans through at least one of said openings into an operative position,means for retracting said second rotatable contact means from anoperative to an inoperative position by withdrawing from at least one ofsaid openings, engagement means for accommodation of the end of saidspindle means opposite said formed end for preventing lateral movementof said spindle means relative to the body yet allowing movement in aplane normal to said body.

2. An integral, mobile drafting instrument as described in claim 1wherein said first rotatable contact means are wheel means and saidspindle means passes through the center thereof.

3. An integral, mobile drafting instrument as described in claim 2wherein said wheel means are comprised of a plurality of frictionwheels, said friction wheel being associated with at least a pluralityof said openings passing through the body and being of lesser dimensionthat the openings so as to be able to pass through said openings.

4. An integral, mobile drafting instrument as described in claim 2wherein said means for accepting an extraneous force in a sleeve meanspositioned about said spindle means in loose slideable associationtherewith.

5. An integral, mobile drafting instrument as described in claim 2wherein said means for retracting said first rotatable contact means aremagnetic means positioned in spatial relationship above said body.

6. An integral, mobile drafting instrument as described in claim 5wherein said spindle means are composed at least in part of a ferrouscompound.

7. An integral, mobile drafting instrument as described in' claim 2wherein said means for preventing lateral movement of said firstrotatable contact means are a plurality of abutment means positioned atboth ends of said spindle means to engage said ends of the spindle meansso as to prevent lateral movement thereof, and resilient spring meanssituated between one of said abutment means and said first rotatablecontact means.

8. An integral, mobile drafting instrument as described in claim 2wherein said second rotatable contact means are wheel means and saidspindle means passes through the center thereof.

9. An integral, mobile drafting instrument as described in claim 8wherein said wheel means are comprised of a friction wheel, saidfriction wheel being associated with at least one of said openingspassing through the body and being of smaller dimension than theopenings so as to be able to pass through said openmgs.

10. An integral, mobile drafting instrument as described in claim 8wherein said means for accepting an extraneous force is a sleeve meanspositioned about said spindle means in loose slideable associationtherewith.

11. An integral, mobile drafting instrument as described in claim 8wherein said means for retracting said rotatable contact means aremagnetic means positioned in spatial relationship above the body.

12. An integral, mobile drafting instrument as described in claim 11wherein said spindle means are composed at least in part of a ferrouscompound.

13. An integral, mobile drafting instrument as described in claim 2wherein said engagement means for accommodation of one end of thespindle means is an abutment means secured to the body, said abutmenthaving an elongated indent therein extending normal to the plane of thebody for accommodating the end of the spindle opposite the formed endthereof 14. An integral, mobile drafting instrument as described inclaim 1 wherein said straight edge portion and said circular portion areprovided with predetermined marking indicia about the edges thereof.

15. In an internal, mobile drafting instrument, a means for drawingcurved lines and predetermined angles, comprising:

a body, said body having a straight edge portion and a circular portion,said body having plurality of openings passing therethrough;

rotatable contact means carried by said body, said rotatable contactmeans having spindle means rotatably secured thereto, said spindle meanshaving one end thereof formed normally to the axis of said spindle meansso as to be slideably accommodated in an opening passing through thebody, said opening being located at the radial center of said circularportion;

means for accepting an extraneous force carried by said spindle meansfor lowering said rotatable contact means into an operative positionthrough at least one of said openings;

means for retracting said rotatable contact means from an operative toan inoperative position by withdrawing from at least one of saidopenings; and

engagement means for accommodation of one end of said spindle means forpreventing lateral movement of said spindle means relative to said bodyyet allowing movement in a plane normal to said body whereby when saidrotatable contact means are in an operative position they serve as meansto move said drafting instrument over the drawing media. 16. In anintegral, mobile drafting instrument as described in claim 15 whereinsaid rotatable contact means are wheel means comprised of a frictionwheel being associated with at least one of said openings passingthrough the body and being of smaller dimension than the openings so asto be able to pass through said openings, and said spindle means passesthrough the center thereof.

17. In an integral, mobile drafting instrument as described in claim 15wherein said means for accepting an extraneous force is a sleeve meanspositioned about said spindle means in loose slideable associationtherewith.

18. In an integral, mobile drafting instrument as described in claim 15wherein said means for retracting said rotatable contact means aremagnetic means positioned in spatial relationship above the bodyv 19. Inan integral, mobile drafting instrument as described in claim 18 whereinsaid spindle means are composed at least in part of a ferrous compound.

20. In an integral, mobile drafting instrument as described in claim 15wherein said engagement means for accommodation of one end of thespindle means is an abutment means secured to the body, said abutmenthaving an elongated indent therein extending normal to the plane of thebody for accommodating the end of the spindle opposite the formed endthereof.

21. In an integral, mobile drafting instrument, a means for drawingstraight lines, comprising:

a body, said body having a straight edge portion provided with aplurality of openings passing therethrough;

rotatable contact means attached to said body. said rotatable contactmeans having spindle means secured thereto;

means for accepting an extraneous force carried by said spindle meansfor lowering said rotatable contact means into an operative positionwherein said contact means pass through said openings;

means for retracting said rotatable contact means from an operative toan inoperative position by withdrawing said rotatable contact means fromsaid openings, said means for retracting said rotatable contact meansbeing magnetic means positioned in spatial relationship above said body;and

means for preventing lateral movement of said rotatable contact means.

22. In an integral. mobile drafting instrument, as described in claim 21wherein said rotatable contact means are wheel means comprised of aplurality of friction wheels, said friction wheel being associated withat least a plurality of said openings passing through the body and beingof lesser dimension than the openings so as to be able to pass throughsaid openings, and said spindle means passes through the center thereof.

23. In an integral, mobile drafting instrument as described in claim Zlwherein said means for accepting an extraneous force is a sleeve meanspositioned about said spindle means in loose slideable associationtherewith.

24. In an integral, mobile drafting instrument as described in claim 21wherein said spindle means are composed at least in part of a ferrouscompound.

25. In an integral, mobile drafting instrument as described in claim 21wherein said means for preventing lateral movement of said rotatablecontact means are a plurality of abutment means positioned at both endsof said spindle means to engage said ends of the spindle means so as toprevent lateral movement thereof, and resilient spring means situatedbetween one of the said abutment means and said rotatable contact means.

1. An integral, mobile drafting instrument, comprising: a body, saidbody having a straight edge portion and a circular portion, said bodyhaving a plurality of openings passing therethrough, a first clutchmeans carried by said body for providing forward motion to said bodyrelative to a drawing media or the like upon the application of anextraneous force thereto, said first clutch means being comprised offirst rotatable contact means having spindle means secured thereto,means for accepting an extraneous force carried by said spindle meansfor lowering said rotatable contact means through said openings into anoperative position, means for retracting said first rotatable contactmeans from an operative to an inoperative position by withdrawing fromsaid openings, means for preventing lateral movement of said firstrotatable contact means due to transient forces, and a second clutchmeans carried by said body for providing rotational motion to said bodyrelative to a drawing media or the like upon the application of anextraneous force thereto, said second clutch means being comprised of asecond rotatable contact means having spindle means rotatably securedthereto, said second rotatable means situated in the same plane as saidfirst rotatable contact means, the axis of rotation of said secondrotatable contact means being angled with respect to the axis ofrotation of said first rotatable contact means, said spindle meanshaving one end thereof formed normally to the axis of said spindle meansso as to be slideably accommodated in an opening passing through thebody, said opening being located at the radial center of the circularportion of the body, means for accepting an extraneous force carried bysaid spindle means for lowering said second rotatable contact meansthrough at least one of said openings into an operative position, meansfor retracting said second rotatable contact means from an operative toan inoperative position by withdrawing from at least one of saidopenings, engagement means for accommodation of the end of said spindlemeans opposite said formed end for preventing lateral movement of saidspindle means relative to the body yet allowing movement in a planenormal to said body.
 2. An integral, mobile drafting instrument asdescribed in claim 1 wherein said first rotatable contact means arewheel means and said spindle means passes through the center thereof. 3.An integral, mobile drafting instrument as described in claim 2 whereinsaid wheel means are comprised of a plurality of friction wheels, saidfriction wheel being associated with at least a plurality of saidopenings passing through the body and being of lesser dimension that theopenings so as to be able to pass through said openings.
 4. An integral,mobile drafting instrument as described in claim 2 wherein said meansfor accepting an extraneous force in a sleeve means positioned aboutsaid spindle means in loose slideable association therewith.
 5. Anintegral, mobile drafting instrument as described in claim 2 whereinsaid means for retracting said first rotatable contact means aremagnetic means positioned in spatial relationship above said body.
 6. Anintegral, mobile drafting instrument as described in claim 5 whereinsaid spindle means are composed at least in parT of a ferrous compound.7. An integral, mobile drafting instrument as described in claim 2wherein said means for preventing lateral movement of said firstrotatable contact means are a plurality of abutment means positioned atboth ends of said spindle means to engage said ends of the spindle meansso as to prevent lateral movement thereof, and resilient spring meanssituated between one of said abutment means and said first rotatablecontact means.
 8. An integral, mobile drafting instrument as describedin claim 2 wherein said second rotatable contact means are wheel meansand said spindle means passes through the center thereof.
 9. Anintegral, mobile drafting instrument as described in claim 8 whereinsaid wheel means are comprised of a friction wheel, said friction wheelbeing associated with at least one of said openings passing through thebody and being of smaller dimension than the openings so as to be ableto pass through said openings.
 10. An integral, mobile draftinginstrument as described in claim 8 wherein said means for accepting anextraneous force is a sleeve means positioned about said spindle meansin loose slideable association therewith.
 11. An integral, mobiledrafting instrument as described in claim 8 wherein said means forretracting said rotatable contact means are magnetic means positioned inspatial relationship above the body.
 12. An integral, mobile draftinginstrument as described in claim 11 wherein said spindle means arecomposed at least in part of a ferrous compound.
 13. An integral, mobiledrafting instrument as described in claim 2 wherein said engagementmeans for accommodation of one end of the spindle means is an abutmentmeans secured to the body, said abutment having an elongated indenttherein extending normal to the plane of the body for accommodating theend of the spindle opposite the formed end thereof.
 14. An integral,mobile drafting instrument as described in claim 1 wherein said straightedge portion and said circular portion are provided with predeterminedmarking indicia about the edges thereof.
 15. In an internal, mobiledrafting instrument, a means for drawing curved lines and predeterminedangles, comprising: a body, said body having a straight edge portion anda circular portion, said body having plurality of openings passingtherethrough; rotatable contact means carried by said body, saidrotatable contact means having spindle means rotatably secured thereto,said spindle means having one end thereof formed normally to the axis ofsaid spindle means so as to be slideably accommodated in an openingpassing through the body, said opening being located at the radialcenter of said circular portion; means for accepting an extraneous forcecarried by said spindle means for lowering said rotatable contact meansinto an operative position through at least one of said openings; meansfor retracting said rotatable contact means from an operative to aninoperative position by withdrawing from at least one of said openings;and engagement means for accommodation of one end of said spindle meansfor preventing lateral movement of said spindle means relative to saidbody yet allowing movement in a plane normal to said body whereby whensaid rotatable contact means are in an operative position they serve asmeans to move said drafting instrument over the drawing media.
 16. In anintegral, mobile drafting instrument as described in claim 15 whereinsaid rotatable contact means are wheel means comprised of a frictionwheel being associated with at least one of said openings passingthrough the body and being of smaller dimension than the openings so asto be able to pass through said openings, and said spindle means passesthrough the center thereof.
 17. In an integral, mobile draftinginstrument as described in claim 15 wherein said means for accepting anextraneous force is a sleeve means positioned about said spindle meansin loose slideable asSociation therewith.
 18. In an integral, mobiledrafting instrument as described in claim 15 wherein said means forretracting said rotatable contact means are magnetic means positioned inspatial relationship above the body.
 19. In an integral, mobile draftinginstrument as described in claim 18 wherein said spindle means arecomposed at least in part of a ferrous compound.
 20. In an integral,mobile drafting instrument as described in claim 15 wherein saidengagement means for accommodation of one end of the spindle means is anabutment means secured to the body, said abutment having an elongatedindent therein extending normal to the plane of the body foraccommodating the end of the spindle opposite the formed end thereof.21. In an integral, mobile drafting instrument, a means for drawingstraight lines, comprising: a body, said body having a straight edgeportion provided with a plurality of openings passing therethrough;rotatable contact means attached to said body, said rotatable contactmeans having spindle means secured thereto; means for accepting anextraneous force carried by said spindle means for lowering saidrotatable contact means into an operative position wherein said contactmeans pass through said openings; means for retracting said rotatablecontact means from an operative to an inoperative position bywithdrawing said rotatable contact means from said openings, said meansfor retracting said rotatable contact means being magnetic meanspositioned in spatial relationship above said body; and means forpreventing lateral movement of said rotatable contact means.
 22. In anintegral, mobile drafting instrument, as described in claim 21 whereinsaid rotatable contact means are wheel means comprised of a plurality offriction wheels, said friction wheel being associated with at least aplurality of said openings passing through the body and being of lesserdimension than the openings so as to be able to pass through saidopenings, and said spindle means passes through the center thereof. 23.In an integral, mobile drafting instrument as described in claim 21wherein said means for accepting an extraneous force is a sleeve meanspositioned about said spindle means in loose slideable associationtherewith.
 24. In an integral, mobile drafting instrument as describedin claim 21 wherein said spindle means are composed at least in part ofa ferrous compound.
 25. In an integral, mobile drafting instrument asdescribed in claim 21 wherein said means for preventing lateral movementof said rotatable contact means are a plurality of abutment meanspositioned at both ends of said spindle means to engage said ends of thespindle means so as to prevent lateral movement thereof, and resilientspring means situated between one of the said abutment means and saidrotatable contact means.